Improvement in bark-mills



ILPETERS. PHOTO-LITHOGRAPMER, WASHINGTON, D C,

GILBERT PALEN AND rLonELLo r." AVERY, or T UNKHANNOCK PENNSYLVANIA.

Letters Patent No. 111.239, dated January 24, 1871.

IMPRovr-:MENT meaux-Muis.-

'The Schedule referred to `tix-these Letters yPatent and making partf o the same.

4vented. a new and improved Bark-Mill; and we do A hereby declare that thefollowing is a full, clear, and

exact description thereof, which-will enable' others skilled in the Aart-to make and use the same, refer' ence being vhad to the accompanying drawing fojrmingpart of this specitication, in whichi- Figure l represents a vertical centralv section of our improved bin'kimill.v

Figure 2 isa plan or -top view partly in section 'oi' the same. i

Figure Sis tin inverted plan view, partly insection, of the stationary grinder.

Figure 4 ism. detail'side view of the apparatus. v

Figure 5 is adeta'il plan view of aportion of the rotary grinder.

. Figure (iis a vertical section through one of the 'teeth ofthe rotary grinder.-

The object of this.A invention is `to improve the machines for grinding bark in such manner that they c an be adjusted to any exten'tn'eadily repairedand be perfect in their operation.

The invention consists in the introduction of various details of' construction, as hereinafter more fully set -fortl1. A in the drawing represents the hopper of our improved bark-mill. This hopper is Amadewider in the middle than'it is'atthe upper and lower ends. This is an advantage', as the contents Ycannot beworkedl outward by the rotary stirrers, and as they are proptracted lower part.

If the hopper is largest at the upper end, its con` tents will readily work out by the stirrers.

erly fed toward the center of the grinder by the con-- To, the l ower end ot' the liopperissecured an ex-v tension ring, B, which at its lower edge carries `the stationary annular grinder C.

'lhe grinder-ring G has outward-'projecting iianges' a, which are, by mean's of screws I), secured t'o similar tlanges that project from the ring B. lhe la'tter is ina similar manner secured Vto the bodyof the hopper.

Heretofore the stationary grinder was generally formed and made in one piece with the body of the hopper.

.if any portion ofthe lower part was broken, the enl tire hopper was useless, and had to be replaced. By our plan the most exposed part is made in form of the ring B, and it' that should be broken by the excessive inhternal strain it can readily be replaced, while all the other parts may be retained. If Athe stationary grinder should be worn, it can be replaced Withoutrequiring a new hopper. g

Lhe upper part of the mill, consisting of the parts A B O just named, is placed upon the cupD, -which is to receive the ground bark. l

lhecup is rmly secured iu or upon the supporting-frameE. -It hasa projectingledge, c, which ts into a,groove ofthe ring C, to form a close-joint. .outside the cup has projecting cars (l d, with inclined upper surfaces, and the ring O has corresponding ears c, with inclined lower faces. The ears e rest upon d,

and are secured thereto by screws f, as =shown in fig.

TheI grinding-shaft 1F rests in a socket which is provided in the center of the cup D, and is steadicd by a ring, g, formed by the inner radial arms, h, of

the ring C and the bushing in the cup. '1). V imilar letters of reference indicate corresponding The lower end ofthe shaft issupported` by a plate, i, which rests on aconvex projection or bump, j, that projects frorn-the bottom of the socket..v The plate t' can thus rockupon the bump j, and will therefore. always be self-adj usting to end of the shaft. `'lhis stepping is only applicable to mills driven from` above, those drivenfrom below being provided with a squareended shaft, as in ordinary mills.

The bushing in cup D is provided for the purpose 'of securing the cup from wear, and can be replaced from above, .theirfront or grinding-faces being radial to the center of the grinder. From the upright grind-- ing surface they gradually shutdownward'toward the` back end. The bark tobe ground is, by the centrifugal force, thrown Voutward from the center;A that crushed by one-tooth is thrown oii into the space between that tooth and the next outer row, and as it is further thrown outward it is nallytakeu up bythe tooth of the next row and crushed, andthenthrown into the next row, dto. f

-Radially the teeth are not in line, so that whatever bark leaves. one row will pass on to the next, and cannot be skipped by 'any one row,

On the In longitudinal section the teeth appear as in fig-6, with their grinding-surfaces nearly upright.

The spaces between the several concentric rows of teeth l are cleaned .by ears m projecting downward from the arms l1.. .The under side of this grinder is provided with a scraper, to keep the ground bark fromf accumulating in the cup. D, and upon the bushing.

Upon the upper part of the shaft F is mounted a ring, fn, which carries a series ofstirrers, H H, and projecting above them an oblique horn, I, whereby the large pieces of bark are broken. This horn and the stirrers act inconjunction with ribs o o, which are -formed on the inner faces of the hopper and rings B and-C. This horn prevents the unground bark from lodging on the stirrers and float-ing o1' riding around,

' and keeps the rotary grinder supplied with bark as y ing its passage outward through the uishing teeth.

The stirrers have*downward-projecting teeth Vlr on their lower faces, which act in conjunction with upwardproiecting teeth s onV the arms h, to break the coarse bark. These teeth are conical in form, so as to make them open o r close more evenly all around by moving the stirrer-up or or down ou the shaft. i

Having thus described our invention,

lVe claim as new and desire to secure by Letters Patentl, The hopper A, the flanged extension-ring B b, and flanged, grooved, stationary grinder C a e, combined as described, with a-cup, D d, rotary grinder G, and shaft F, for the purpose specified.

'2. The hopper A, dialnetrcally larger in the middle than at each end, and having theribs o thereon,.oom bincd as described with a bark-breaking, oblique, and rotating horn I, for the pnrposespecied.

' G. E. FALLEN.

lf. l. AVERY.

Vitnesses'i F. G. Ross, T. W. FLICKNEP.. 

